Characterization of the icosahedral quasicrystal in the rapidly solidified Mg-Al-Zn ternary alloy

摘要

By means of XRD, SEM, FE-SEM, and TEM, the microstructures and growth morphology features of icosahedral quasicrystal for rapidly solidified Mg-Al-Zn system were investigated. It was found that, single icosahedral quasicrystal can be obtained in the Mg-Al-Zn alloys. The icosahedral quasicrystal reveals three typical morphologies: well developed dendrites, coral-like, and petal-like, and its compositions are in a wide range composition with 42.87-48.89 at.%Mg, 13.78-17.03 at.% Al, and 34.22-40.60 at.%Zn. Pentagonal dodecahedron with icosahedral symmetries is seen, and certain steps in pentagonal faces suggest that the planar growth occurs on the pentagonal faces.